Surgical Resection with Posterior Rectus Sheath Preservation and Mesh Reconstruction without Pursuing Wide Negative Margins for an Abdominal Wall Desmoid in Familial Adenomatous Polyposis: A Case Report.

INTRODUCTION: Desmoid tumors are locally aggressive, non-metastatic neoplasms that develop in up to 20% of patients with familial adenomatous polyposis (FAP). While active surveillance is the initial approach, surgery may be indicated for symptomatic or progressive disease; however, the optimal surgical strategy remains debated. CASE PRESENTATION: We present the case of a 48-year-old man with FAP and a history of two previous laparotomies. He developed a progressive and symptomatic abdominal wall desmoid tumor refractory to non-operative management, including medical therapy. He underwent a surgical resection without pursuing wide negative margins. Intraoperatively, the tumor was adherent to the prior midline incision scar and anterior rectus sheath. After resection, the resulting 100 × 50 mm fascial defect was repaired with a synthetic mesh. Histopathology confirmed the desmoid tumor with microscopically negative (R0) resection margins, and no evidence of recurrence was observed at the 9-month follow-up. CONCLUSIONS: Surgical resection without pursuing wide negative margins, previously described in sporadic desmoids, may be considered a feasible option for selected FAP-associated abdominal wall tumors, balancing local control with no apparent postoperative abdominal wall functional deficit.